Electrical resistor and method of making same



Nov. 21, 1950 J. J. CERNY 2,531,321

ELECTRICAL RESISTOR AND METHOD OF MAKING SAME g as a m 25 FR :4 I v I /d iyzay Patented Nov. 21, 1950 ELECTRICAL RESISTOR AND METHOD OF MAKING SAME Joseph J. Cerny, Chicago, Ill.

Application June 28, 1948, Serial No. 35,714

12 Claims.

This invention is directed to novel resistors, particularly of the type adapted to be used in a Wide variety of devices, electrical apparatuses, and electrical circuits, and appliances, in which a relatively great degree of accuracy is required in the resistors therein used.

It is an important object of my invention to provide a resistor, in which the degree of accuracy is relatively very great, by pro-determining the resistance in the wire to be effectively used. More primarily my invention is directed to a novel method or process of more quickly and economically manufacturing portable resistance units in which the degree of accuracy is very great.

A further object and accomplishment of my invention is the provision of resistors adapted to be connected in electrical circuits, said resistors including an elongated body, metal end caps mounted on the respective ends thereof, terminal circuits wires, and a resistance wire of pre-determined resistance.

A further object and accomplishment of my invention is the provision of a novel method of rapidly manufacturing resistors, for electrical circuits, in which the initial forms of the resistors include a non-conductive core into the ends of which terminal circuit wire having been irremovably set, and which method provides for anchoring a resistance wire at the opposite ends thereof to said terminal circuit wires, connecting said aforedescribed structures in circuit with an ohmmeter, winding said resistance wire around said terminal wires until a required resistance is registered, and then winding the remaining resistance wire upon said core.

- It is a further object and accomplishment of my invention to provide a resistor in which induced magnetic fields do not affect the resistance of said resistor, by uniformly spirally winding one-half of said resistance wire in one direction upon the core, and by spirally winding the other half thereof in an opposite direction so that the magnetic fields set up will equalize each other.

A further object of my invention is to provide a novel core or body in a resistor so that the resistance wires which are wound about said core may be securely anchored so that said resistance wire will not slip off said core.-

It isa further object of my invention to provide a novel resistor of great accuracy in which the end caps thereof are of a shape to render said resistor not useless in the event the circuit wires thereof break off, but providing each of said end caps with an integral outwardly extending flange through which said terminal circuit wires pass. In the event of breaking therefore, of said terminal wire, said breaking will most probably occur adjacent to said outwardly extending flange. My novel construction and method herein described is adaptable to a large variety of sizes of resistors, and because of the method employed, laboring costs, which are a sizeable portion of the cost of the resistors, of the type herein described, may be substantially reduced.

Other and further important objects of my invention will be apparent from the following description and appended claims.

One embodiment of my invention is illustrated in the accompanying drawings bearing numbers of reference referred to in the accompanying specification.

On the drawings,

Fig. 1 is a cross sectional view of the core showing the circuit wires embedded.

Fig. 2 is a front elevation of my core winding device.

Fig. 3 is an elevational view of the core in the final stage of being wound with resistance wire.

Fig. 4 is an elevational view showing the core and one terminal end cap placed thereon.

Fig. 5 is a detailed view showing the relation of the parts, with part of the non-conductive covering removed.

Fig. 6 is a completed view of my resistor.

Referring to the drawings, reference numeral l0 designates cylinder, or rounded core, or body, made of a suitable non-conductive material such as a thermo plastic or thermo setting resin. Said body it! may vary widely in its dimensions de-' pendent upon the size of resistor required. As illustrated in Fig. 1, terminal circuit wires H are embedded into the substance of the core or body It, one of said wires being positioned in one end thereof and the other of said wires being posi tioned or set into the opposite end thereof. The wires l8 are preferably set into the core during the manufacture thereof, preferably while the substance or material of which said core is made is in a tacky state, before the setting and solidifying thereof. Said terminal wires I I are preferably centered with respect to their respective ends of said core; and said wires preferably extend outwardly of said coe asa continuation of the longitudinal axis thereof. Preferably each of the terminal wire ends or pigtails II is formed in the shape of a J, to provide an anchoring member withthe shorter leg l2 of said J-shaped wires entending laterally of the core for a slight distance, said shorter leg 1 2 being preferably parallel to the longer leg. of saidwire II and preferably spaced therefrom by substantially the diameter of the wire H, as illustrated in Figs. 1, 2, and 3.

As illustrated in Fig. 2, numeral 13 represents a vertical board, brace, or support mcmber, or its equivalent, which is preferably made of some non-conductive material, and which is preferably suitably mounted in any appropriate fashion to assure rigidity. A conductive expansion spring or its equivalent l4 ismounted on preferably the upper portion of saidsupport [3," preferably by means of a bracket 28, and a retainmg screw and nut designated generally as 21. Preferably two immovable non-conductive pins orrmembers. [5.

are removably positioned in a substantially horizontal line on the front face of support member l3. Said pins l5 are spaced apart slightly more than the length of the core [9. It isto be understood that the pins 1 5 may be set in said support to correspond to any variety of core sizes.

As illustrated in Fig. 2; numeral l6 represents apair" of rotatable holding or grippingmembers,- suchzas'chucks orarbors, one of which members grips theunembeddedend of one ofthe wires l l, and the-other of which'members grips the unembedded end of the other of said wires H during; the: normalwinding operation. Gripping members I6. are preferably mechanicallyrotatable.-

With the embedded, wires gripped as aforedescribed the respective-ends of resistance wire IT- are anchored on the opposite wires II by anchoring or lockingsaid resistance wires in any suitable manner-to the leg 12 of the wire H and thebody-ofthe wire II. Anintermediate: portiOIttOf'thQ'WiIS ll is preferably anchored to lowermost portion of the spring It so that/said wire during the normal operations assumes the shapei-of an inverted-V. The wire I! is preferably sufficien-tly short so that, at all times'duringz-the process; atension or pull is.created on the spring [4 while the core I is held suspended between thechucks l8. By placing th pins l man-appropriate position, the opposite end poritions-22 of the-wire I 1 becomes substantially parallel to:each,other-asillustrated in Fig. 2.

Aszillustrated. in- Fig. 2 the circuit wires H are connected in seriest-toan o-hmmetenor any suitable instrument !9 for indicating. resistance; by, means aof appropriate wires designated generally as: l8; It is to be understood that I am not limitingm-yselfto'theuse of an ohm-meter, but that any instrument .or'group of instruments, or their equivalents; for" determining resistance,- may be used;

By turning the chucks, the anchored ends: 22 of the wires I'larewound around the wires H at -substantially the positions where said ends are. anchored, due toguiding by the pins I 5. When theproper length of resistance wire re mains unwound-on the wires H, as determined bya reading-on the-ohmmeter i8, thepins I5 are removed-by an'operator and further winding on the-wires] l is stopped. An'operator then causes thetwo opposite then unwound'end' parts 22; ofrtheresistance wire :I Lto engage'and be, gripped in the'respective'beveled recesses 23, one of which iSFDOSitiOHEdilH eachend of'the core) as 111115-1- trated in Fig: 2. Thisanchoring precludesithe slipping off of theresistance wire from the core I05" As .the-rotation'of the core again commences; the'remaining length of unwound resistance wire I lis wound upon said core, l8. because of the yielding of the spring I 4;

Dueto the aforedescribedprocedure of anchoring thewire, l I 1 uponthe spring-l 4,; the wire H which is wound around the core is disposed in a spiral path on and about the core I0, so that substantially one half of said resistance wire is disposed spirally in a direction opposite to the other one half thereof. The wire I! is wound on the core until said wire has dissipated itself in winding about said core, with the apex thereof being disposed adjacent to the central portion". of said" core Id as',illustrated inFig. 3. Thereupon, said apex is removed from'said spring l4, and is caused to be retained by applying a suitable non-conductive adhesive for causing retentionof-lsaidwire. against said core In. The core. and woundresistance wire are then removed from the gripping members [6, are preferably coated and covered with a suitable nonconductive material 23.

As illustrated in Figs. 4, 5, and 6, numeral 24 represents a metal end cap or member which is preferably formed with an outwardly projecting-annular flange-25 in the bottom thereof. Said flange. 25 defines'an opening in the bottom of said cap whichispreferably centrally disposed. The opening definedby the.flange,25 is of a sufficient. size to: permit the positioning of the wire H, leg l2, andthe anchored end of the Wire- I'Ltherein. Theinnerdiameter of the annular wall .21 of the cap 24 is substantially. the

sameascthediameter of the coreand-resistancewirepassembly, with their non-conductive coating.v

After. the core and resistance wire have been assembled, and preierablyafter the application of a non-conductive coating thereto, .a metalend.

cap 24 is preferably impinged and securely-positioned. on-each-endpfsaid assembly, asillus-' trated in Fig. 4. To furthersecure saidcaps to the wiresl l andthe-endspf the wire. ll anchored thereon-.1 usean appropriate material such as solder.

By my method, I can produce resistors-of relatively.-high.accuracy-at a relatively, lowcost for resistorstof that degree of accuracy.

It isi-torberobservecl: that after determiningitheexact.effective resistance, I preclude the interferenceof-xinduced magnetic fields, with the measured'resistance, by winding the resistance wire-in opposite spiral paths onopposite halves of the core-bodies, causing the effect of electrically equalizing .the. two fields thus set up.

I, apply-a suitable non-conductive coatinggor covering upon the core bodies with the metal end caps thereon; for-example, using material such as porcelain enamel, which, when dried and baked, effectively protects the resistor over. its entire length andleaves only the terminal circuit wires'H projectingtherefrom. Such enamel coating has high heat conductivity and quickly dissipates the heat developed in the resistor element.

It is .to be-understood' thatduring the winding oftheresistance wirell, the ohmmeter [9 may be kept-in series-with said resistance wire woundandiu-nwoundupon .thecore 10 so that any in-- by; as changes'may-be made in the arrangementand proportion of parts, and equivalents maybe substituted without departing from the spirit and scope of the invention.

I claim:

1. A resistor for electrical circuits or the like, a core; a resistance wire wound around said core; a terminal circuit wire mounted on each end of said core and projecting outwardly therefrom; and an end portion of one end of each circuit wire bent back and extending outwardly from said core, said end portions being parallel to said circuit wires and spaced slightly therefrom, said end portions cooperating with said circuit wires providing means for anchoring the opposite ends of said resistance wire.

2. In a resistor for electrical circuits and the like, a core; a resistance Wire of predetermined resistance wound around said core, said resistance wire being wound in slanting spiral paths upon said core, one half of said spiral resistance wire sloping in one direction and the other half thereof slanting in a direction substantially opposite to said first one half thereof; terminal circuit wires mounted on said core and projecting outwardly therefrom; and end leg on each of said wires bent back on said circuit wires and projecting outwardly from said core, said end legs being parallel to said circuit wires respectively and spaced slightly therefrom, said end legs cooperating with said circuit wires to provide means for anchoring the ends of said resistance wire.

3. In a resistor for electrical circuits and the like, a core; a resistance wire wound around said core, said resistance wire being wound in slanting spiral paths upon said core, one half of said spiral resistance wire sloping in one direction and the other half thereof slanting in a direction substantially opposite to said first one half thereof; terminal circuit wires mounted on said core and projecting outwardly therefrom; a short integral leg of each of said circuit wires being bent and extending outwardly of said core, said legs being parallel to said circuit wires respectively and spaced slightly therefrom, said integral legs cooperating with said circuit wires respectively to provide means for anchoring the ends of said resistance wire; a non-conductive coating covering said core and said resistance wire wound thereupon; and end caps securely mounted on each end of said core over said non-conductive coating, said circuit wires projecting therethrough.

4. In a method of making resistors for electrical circuits and the like, of high accuracy, the steps of first measuring an intermediate portion of a resistance wire to a length to correspond to a given resistance and before same has been wound on a core, then securely anchoring the unmeasured ends of said resistance wire to the terminal circuit wires of said core, and winding said intermediate portion on said core having terminal circuit wires projecting therefrom.

5. In a method of making resistors for electrical circuits and the like, of high accuracy, the steps of first measuring an intermediate portion of a resistance wire to a length to correspond to a given resistance; winding said intermediate portion on a core having terminal circuits Wires projecting therefrom, said resistance wire wound on said core being wound in spiral paths so that one-half thereof slants in a direction opposite to the other half thereof; securely anchoring the unmeasured ends of said resistance wire to said terminal circuit wires before winding said resistance wire on said core; covering said core said circuit wires and said anchored ends of said resistance wire. 6. In a method for making resistors for electrical circuits and the like of relatively high accuracy, substantially as recited in claim 4 wherein one half of said resistance wire wound upon said core is wound in spiral paths upon said core, sloping in one direction, and the other half of said resistance wire is wound about said core sloping in a direction substantially opposite tojthe first one half thereof.

7. In a method for making resistors for electrical circuits and the like, of relatively high accuracy, the steps of anchoring the opposite ends of a resistance wire tothe opposite circuit wires of a core body; electrically connecting said anchored resistance wire and said terminal cir- =cuit wires with a resistance measuring mechanisrn; simultaneousl winding the ends pf said resistance wire upon said circuit wires until a length of resistance wire corresponding to a specific predetermined resistance has been reached, and then winding said measured length of resistance wire corresponding to said given resistance on said core body.

8. In a method for making resistors for electrical circuits and the like, of relatively high accuracy, substantially as recited in claim 7, wherein one-half of said measured resistance wire is wound in spiral paths on one-half of said core body and the other half of said resistance wire is wound in spiral paths in a direction substantially opposite to said first half thereof on the other half of said core body.

9. In a method fo making resistors for electrical circuits and the like, of relatively high accuracy, the steps of anchoring an intermediate portion of a resistance wire to a yieldable tension means; anchoring the opposite ends of said resistance wire to the opposite circuit wires of a core body; electrically connecting said anchored resistance wire and said terminal circuit wires with a resistance measuring mechanism; then simultaneously winding said resistance wire ends upon said circuit wires until a length of resistance wire corresponding to a specific pre-determined resistance has been reached; and then spirally winding said measured length of resistance wire corresponding to said given resistance on said core body so that one half of said resistance wire wound upon one half of said core body slopes in a direction opposite to the other half thereof on the other half of said core body.

10. In a method for making resistors for electrical circuits and the like, of a relatively high degree of accuracy. the st ps of securely mounting a conductive terminal circuit wire in each end of a core body; rotatably gripping the ends of said circuit wires; connecting a resistance wire at an intermediate point thereon to a yieldable means: holding the depending end portions of said resistance wire parallel to each other; socurely anchoring the ends of said parallel depending end portions of said resistance wire to opposite circuit wires of said core body, thereby developing a. tension on said yieldablemeans; electrically connecting; said anchored resistance wire andterminalicircuit wires with a resistance measuring mechanism; rotating said core 0 that the endsofvsaid resistance wire are simultaneously wound on said terminal circuit wires until alengthof resistance wire remainsunwound correspondingto a predetermined resistance, as .indicated. by said resistance measuring mechanism; removing the means for holding said ends of said resistance wire parallel to each other so that the remaining resistance. wire isin the r shape 4 of an inyertedzwanchoringthe opposite endsof the unwound r resistance, wire. on vrespective opposite ends of 'saidjcore body; ,then rotating said core so that the cmeasuredrlength of 1 said. resistance wire; is.- wound in spiral pathsupon said core untilsaidyieldablelmeans is drawn adjacent substantially the center. ofjthelength of "said core body, one half 'of'said measured, resistance/wire being woundson substantially one. half of J said core body, and'the. other onehalf of said meas: ured; resistance wire being wound on the other onehalf 0f saidcore body, said second one half of said measured.resistancewire slopingin a direction opposite to the first onehalf thereof; and then securing said intermediate point of said resistancevv wire against said core.

11., In a method .for making resistors and'the like for electrical circuits, and the like, winding 3 the rendsi of'a wire on a conductor until a predetermined electricallyfi measured resistance has 8:: been ..reached in said wire and then 1 winding the remaining portions of said wireon-a corebody.

12. In combination with'a method for making.

electrical resistors and the like, windinga wire on the terminalends of .a core body until a predetermined. electrically measured resistance has been reached in saidtwireand thenwindingthe remainder of said wire on a, core. body s0=that a .portion of saidremainder slopes in onedirection and another portion ofrsaid remainder slopes. in an opposite direction.-

JOSEPH J. CERNY;

REFERENCES CITED The following references are of record in :the file'of this patent:

UNITED STATES PATENTS Number Name Date 483,124 Ahearn Sept..v27, 1892 7 774,140 Thomas Nov. 1,,1904

1,976,514 Pugh Oct. 9, 1934,

2,055,849 Mucher Sept. 29,1936:

2,265,821 Siegel Dec.v9, 1941 2,319,413 Leathers et al May 18, 1943 2,355,611 Veley Aug.,15,1944- 2,431,965 Robbie et al. Dec. 2,1947

FOREIGN PATENTS Number Country Date 595,705 Great Britain Dec.cl2, 19.47 

